Linux find a biggest files in /
sudo du -a /dir/ | sort -n -r | head -n 20
du - estimate file space usage
more here
Summarize disk usage of each FILE, recursively for directories. Mandatory arguments to long options are mandatory for short options too.
-a, --all write counts for all files, not just directories
--apparent-size print apparent sizes, rather than disk usage; although the apparent size is usually smaller, it may be larger due to holes in ('sparse') files, internal fragmentation, indirect blocks, and the like
-B, --block-size=SIZE use SIZE-byte blocks
-b, --bytes equivalent to '--apparent-size --block-size=1'
-c, --total produce a grand total
-D, --dereference-args dereference only symlinks that are listed on the command line
--files0-from=F summarize disk usage of the NUL-terminated file names specified in file F; If F is - then read names from standard input -H equivalent to --dereference-args (-D)
-h, --human-readable print sizes in human readable format (e.g., 1K 234M 2G)
--si like -h, but use powers of 1000 not 1024
-k like --block-size=1K
-l, --count-links count sizes many times if hard linked
-m like --block-size=1M
-L, --dereference dereference all symbolic links
-P, --no-dereference don't follow any symbolic links (this is the default)
-0, --null end each output line with 0 byte rather than newline
-S, --separate-dirs do not include size of subdirectories
-s, --summarize display only a total for each argument
-x, --one-file-system skip directories on different file systems
-X, --exclude-from=FILE exclude files that match any pattern in FILE
--exclude=PATTERN exclude files that match PATTERN
--max-depth=N print the total for a directory (or file, with --all) only if it is N or fewer levels below the command line argument; --max-depth=0 is the same as --summarize
--time show time of the last modification of any file in the directory, or any of its subdirectories
--time=WORD show time as WORD instead of modification time: atime, access, use, ctime or status
--time-style=STYLE show times using style STYLE: full-iso, long-iso, iso, +FORMAT FORMAT is interpreted like 'date'
--help display this help and exit
--version output version information and exit
Display values are in units of the first available SIZE from --block-size, and the DU_BLOCK_SIZE, BLOCK_SIZE and BLOCKSIZE environment variables. Otherwise, units default to 1024 bytes (or 512 if POSIXLY_CORRECT is set).
SIZE may be (or may be an integer optionally followed by) one of following: KB 1000, K 1024, MB 10001000, M 10241024, and so on for G, T, P, E, Z, Y.
PATTERN is a shell pattern (not a regular expression). The pattern ? matches any one character, whereas * matches any string (composed of zero, one or multiple characters). For example, *.o will match any files whose names end in .o. Therefore, the command
du --exclude=aq*.oaq
will skip all files and subdirectories ending in .o (including the file .o itself).